Performance-Boost is reserved for projects that Glitch uses for testing and demos. To preserve overall site performance, we don’t currently offer this to the rest of the community.
In the future, it may be a paid feature option. If that becomes available, we’ll let our users know!
As @tasha said, Performance Boost is only for projects that are used for testing and demos. However you’re asking for extra memory and disk space. This only will happen if you are having having some serious issues with your Glitch project (i.e. cannot install packages due to full container storage, suspended project, full memory etc.), they will grant you that extra amount of quota to fix your Glitch project issues.
So unfortunately, they will not give out extra container quota (memory, disk space) for no important reason on Glitch projects. They may bring in paid features soon that can let you get that extra memory and storage!
Hope this helps